Electromagnetic air puffer valve unit



Feb. 26,1957 E. H. BICKLEY 2,783,021

ELECTROMAGNETIC AIR PUF'FER VALVE UNIT Filed Dec. 11, 1952 INVENTORirerefzlv fi'zzvtiey United States Patent ELECTROMAGNETIC AIR PUFFERVALVE UNIT Everett H. Bickley, Narberth, Pa.

Application December 11, 1952, Serial No. 325,487

3 Claims. (Cl. 251-140) The present invention relates to air controllingvalves and more particularly to a magnetically operated pulfer valveunit for use as an essential part of a machine for color sorting ofobjects at extraordinary high speeds by short puffs of air emitted inrapid succession through the valve in response to selected colorconditions. A machine of this character is shown in applicants PatentNo. 2,580,275, and with which the valve unit of the presentinventiontcan be used in place of the valve unit shown therein. Also,the invention is an improvement in some respects upon the magnetic valveshown in applicants Patent No. 2,615,470. I

An object of the invention is to provide an electromagnetic valve ofimproved construction for use in combination with the colorsorting ofbeans, peas, coiiee, rice, fruit, nuts, or other objects at high speed.

Another object is to provide an improved coil assembly which functionsas a component part of a novel air control valve for releasing pulfs ofair in rapid succession to an outlet leading to a point adjacent anobject inspection point in a color sorting machine.

Another object is to provide a fluid-controlling magnetic valve whereinthe magnetic gap and the fluid outlet are alined in close proximity andat the point of maximum magnetic strength. 1

Still another object is to provide a high speed air pufi'er valvewherein inertia, friction, wear, magnetic and air losses are reduced toa minimum.

A further object is to provide a magnet coil which can be easilyassembled and not only is protected from damage and corrosion whenhandling impure air, but also concentrates the magnetic lines of forcein the armature substantially parallel to the direction of motion of airflow toward the outlet orifice.

Further objects will appear hereinafter in the specification.

In the accompanying drawings Fig. 1 represents a sectional elevation ofa magnetic puffer valve unit embodying one form of the presentinvention; Fig. 2 represents a section on line 22 of Fig. 1; Fig. 3represents an enlarged section of parts shown in Fig. 1; Fig. 4represents a fragmentary section on line 4-4 of- Fig. 3; Fig. 5representsa bottom plan of the unit; Fig. 6 represents a plan of amodified form of armature valve; Fig. 7 represents a plan of a recoilwasher for "association with the armature valve. of Fig. 6; Fig. 8represents a plan of the armature and washer as assembled; and Fig. 9represents a fragmentary section showing the modified form of armaturevalve with its recoil washer as assembled adjacent the outlet of themagnetic unit.

Referring to the drawings, one form of the present invention comprises abase 10, preferably circular in shape of aluminum alloy or brassmaterial having an air inlet 11, a discharge passage 12, and a hole 13for the passage of a two wire cable 14 to supply voltage to the controlmagnet 15 as will hereinafter be described. An outer circumferentialoffset 16 is provided in the upper face of the base 10 to receive agasket 17, against which the peripheral edge of an inverted bell housing18 seats, to provide a leak-proof joint when the latter is fixed inplace through the medium of a U-shaped clamp 20, which terminates inends hooked about the base 10 to clamp the bell housing 18 in place bymeans of a thumb screw 21 threaded centrally through the clamp to bearagainst the top of housing 18. When the housing 18 is thus clamped tothe base 10, it forms an air chamber or reservoir 22 which receives airunder pressure by way of the aforesaid inlet 11. Discharge of air fromthe chamber 22 is by way of the air gap passage 12 in conjunction with atubular outlet nozzle 23. This discharge The diameter of the nozzle 23is such that when as senrbled within the passage 12 it reduces thatpassage to a circular air gap outlet, which has such narrow crosssectionas to approach the dimensions of a slit as toperrnit effective airdischarge with very limited lifting of the valve. That portion of theoutlet nozzle 23 within the passage 12 is provided with two ports 25 tolead the discharged air into the bore 26 of the nozzle 23.

For controlling the discharge of air to the circular passage 12, a valve27 in the form of a magnetic responsive washer-like armature is providedand dimensioned to seat over the upper end of the passage 12 as aclosure, while its center hole slightly overlaps inside the juxtaposedend of the outlet nozzle 23, and its outside slightly overlaps theoutside of the bore 12. The upper face of the valve 27' in oneconstruction is provided with a notch 28 which seats an elongated spring30 so mounted as to bias the valve 27 to closed position. As shown, theends of the spring 36) are respectively anchored to two mounting screws31, the purpose of which will appear later hereproper position to fullyclose the circular air slit when seated. The air pressure within theunit acts also to return the valve to its seat as an auxiliary aidshould there be any relaxing of the spring. Instead of this spring 30 arubber washer may be used, as is described below.

' In order to open the valve 27 against the bias of the spring 30 andthe air pressure inside the chamber, an electromagnet is providedcomprising a ring coil 32 and a surrounding magnetic core, preferablysteel, which together form an entirely new assembly for a maximummagnetic focus at the valve air gap with consequent rapidsensitiveaction. The steel core is formed by a steel band 33 encirclingthe side of coil 32 as a protecting enclosure, such band may be in theform of a tube for telescoping about the coil, but is preferably a bandlengthat the top by a steel or like magnetic metal plate 36 welded orotherwise made fast to the band and having a central aperture 37in axialalinement with the central: hole of the coil'32. The-side of this coilhole is pro-" tected by a tube 38 of steel attached at its upper end tothe plate 36 with its bore 49 registering with the aperture 37 in theplate 36. The bore 40 provides a passage for air to discharge into closeproximity to the valve 27. The length of the tube 38 is such that itslower end protrudes below the coil 32 to form a relatively small air gapwith the valve 27. Preferably the tube 38 is slit lengthwise to stopeddy currents, and this slit communicates with a radial slit 41 in theplate 36 for the same purpose. Both Patented Feb. 26, 1957.

slits are very fine and may be filled with insulating material.

The lower end of the coil 32 is protected by a plate 42 marginallyattached to the band 33, by welding or otherwise, and has a central holeencircling the protruding.

end of the tube 38 in spaced relation to form a magnetic air gap 43 inregister with the valve 27, such gap 43 being of slit-like dimension.The plate 42, like the top plate 36, is formed with a like fine radialslit to stop eddy currents. Preferably, a paper washer 45 is disposedbetween the valve 27 and the plate 42 and encircles the said magneticgap 43 to prevent residual magnetism from causing the valve to stick.While the magnet core has been described as individual parts,interconnected, the core is actually a complete unitary member enclosingthe coils externally and internally except for the magnetic gap 43 inthe bottom plate 42.

For mounting the coil 32 with its associated band parts, the lower faceof the plate 42 is provided with internally threaded bosses 46 toreceive the mounting screws 31 which pass through the base 10 forclamping purposes. One such screw 31 also serves to attach a mountingsocket 47 by which the whole assembly is supported conveniently withrespect to the sorting machines inspection point. The cable 14 forms anenergizing circuit for the coil 32 in accordance with signals receivedfrom the signal equipment. The signal equipment includes a controlcircuit including one or more thermionic tubes and a photo-electriccell, which latter controls the input of the tube or tubes, as it scansa succession of beams travelling in rapid row succession past theinspection point where the discharge nozzle from the putter air outletis located, to segregate beans of like color into one of tworeceptacles.

With beans travelling at a high rate of speed, it is obvious that thevalve must operate instantaneously. By the present invention the lift ofthe valve may be very small in amount but this alone will not contributeto the instantaneous action necessary unless the magnetic air gap anddischarge air gap in conjunction with the focussed maximum magneticforce developed by the novel coil assembly cooperate as a combination toproduce the new result.

Particular attention is directed to the spacing of the armature valve 27with respect to the electromagnetic air discharge outlet because thejuxtaposed relation of these parts forms an air gap of very smallproportions. When the valve opens there are two air discharge paths; thehole of the armature on the inside, and the other from the outside ofthe armature, peripherally.

In the form of the invention shown in Figs. 6 to 9 the armature valve 27is also in the form of a washer dimensio'ned to control the passage 12but is provided with radially projecting cars 50 to the top surface ofwhich an elastic washer 51, preferably rubber, is cemented to functionas a means to bias the valve to closed position. When assembled as shownin Fig. 9 the washer 51 seats against the lower face of the plate 42 andis held against lateral displacement by outwardly flaring the peripheraledge of the air gap 43 so that it enters the hole in the washer 51. Asso assembled the rubber washer 51 encircles the annular flaring and theplate in contact relation maintaining the valve 27 accurately inregister with the passage 12. A lift of the valve by energization of thecoil opens the valve 27 and compresses the washer 51 so that when thecoil is deenergized the washer 51 recoils to close the valve. It isdesirable to have the valve open and close at about the same flow ofcurrent in the coil. Since the magnetic attraction increases veryrapidly as the armature approaches the pole pieces, hence when therubber is compressed, the resistance runs up very fast in practicallymatching relation to the flow of current.

The ultimate result of the conjoint action of the washer type armature,the narrow circular discharge passage, and the associated similar airgap, makes it possible to produce a valve lift of very small proportionswhereby the puffs of air can be discharged in rapid succession and at aspeed heretofore unapproached by any previous valve for sorting beans atrates commercially demanded.

Having thus described my invention, I claim:

1. An air putter unit to produce short putts of air at extremely highspeed for association with a machine for color sorting of objectscomprising a base, an inverted bell housing formed with said base asealed air reservoir, an air inlet through said base leading to saidchamber, an air outlet through said base, a tubular nozzle mounted insaid outlet to form a slit-like concentric discharge passage encirclingsaid nozzle, said nozzlc having a port communicating with said passage,a valve in the form of a washer of magnetic material positioned tocontrol said concentric passage, means biasing said washer to closedposition, an clectro-magnet, to lift said valve to open said passage torelease air from said chamber, said magnet providing a gap in closeproximity to said valve and at the area of maximum magnetic field.

2. An air puller unit in accordance with claim 1 wherein theelectromagnet comprises a ring coil and a core of magnetic materialabout said coil having a central hole axially alined with the passagefor discharge of air into said passage when the valve is open, said corealso forming a magnetic air gap encircling an end of said hole in closeproximity to said air discharge gap.

3. An air putter unit to produce extremely rapid short puffs of air forassociation with color sorting mechanism. comprising the combination ofa magnet coil, a core of magnetic material enclosing said coil andforming an axially disposed air passage and an annular magnetic gapencircling one end of said passage, 21 housing for said coil forming asealed chamber having an inlet for air under pressure and a cylindrical;outlet communicating with said gap and axially alined with said passage,a tubular nozzle having a closed end terminating in said outlet andhaving a. lateral port communicating with said outlet, an armature discvalve seating over said outlet having an aperture alined with saidpassage, said valve opening said outlet when said coil is energized, andmeans for restoring said valve to closed position when said coil isdeenergizcd.

References Cited in the tile of this patent UNITED STATES PATENTS 52,957Bridge Mar. 6, 1866 661,603 Gold Nov. 13, 1900 2,261,562 Ray Nov. 4,1941 2,339,352 Ray Jan. 18, 1944 2,370,752 Ray Mar. 6, 1945 2,565,954Dey Aug. 28, 1951 2,615,470 Bickley Oct. 28, 1952 FOREIGN PATENTS615,997 Great Britain Jan. 14, 1949

